路透社华盛顿健康消息 虽然科学家们在几年前就发现，男女孩的青春期比以前提前了，但他们并不知道是什么原因造成的以及会造成什么样的后果。
1997年，一项针对17,000名女孩所做的重要研究发现，女孩的青春期开始的平均年龄为9.7岁，比过去对白人女孩所做的研究结论提早了一岁。美国黑人女孩青春期开始年龄更早，平均才8岁。虽然这些年来关于儿童，尤其美国黑人孩子青春期开始年龄的数据很不足，但该研究的带头人，美国卡罗莱那州北部一所大学的马西娅·赫而曼吉登教授确信，全球儿童青春期开始的年龄提前且持续时间延长的趋势确实存在。她目前正在分析美国男孩子的数据。
专家认为，这将是一个严重的公共卫生问题。人们还没有认识青春期提前将对身体和心理健康所造成的长期影响。研究发现，肥胖和超重跟早熟有关，也许是一个潜在的因素。另外，其他包括遗传，低出生体重，营养不良，缺乏运动。家里没有父亲或家里有与孩子没有亲戚关系的男性也被认为是相关因素。
科学家们目前正在探索“内分泌干扰物质”，一些被认为可影响人体激素功能的化学物质，会提前或延迟青春期的时间。在这些化学物质中，最有争议的是酞酸酯。酞酸酯是一类能在玩具、乙烯地板、清洁剂、化妆品和护肤剂中找到的化学物质。有学者认为，这些化学物质可造成老鼠胎儿性发育延迟。化工和化妆行业则声称，酞酸酯已被证实不会导致青春期的提前。
尽管对“内分泌干扰物质”与青春期提前之间的关系还没有肯定的科学依据，但研究发现两者之间确有可能的关系。过去也有研究表明，女孩子青春期提前容易过早开始约会，过早发生性行为，容易遭受更多的心理压力，也会发生更多的错误行为，更容易染上抽烟喝酒的陋习。
同时，青春期提前也迫使父母提前对子女进行性教育。专家指出，青春期提前的孩子，外表看起来似乎成熟了，但他们在心理上仍然还是小孩。
Ever-Younger Puberty Puzzles Researchers
WASHINGTON (Reuters Health) - Scientists have known for several years that girls and boys are reaching puberty earlier, but they still don‘t know why this is happening, or what the consequences might be, experts said at a forum here Monday.
In 1997, a landmark study of 17,000 girls found that the average starting age of puberty had dipped a year from previous studies of Caucasian girls, to 9.7 years.
African-American girls hit puberty even earlier, at an average age of about 8, said Marcia Herman-Giddens, principal author of that study and a professor at the University of North at Carolina Chapel Hill.
Data on when puberty starts has been skimpy over the years--especially for African Americans. But, said Herman-Giddens, ``I‘m confident that this trend is a real trend,‘‘ adding that adolescence seems to be starting earlier and lasting longer in children worldwide. She is currently analyzing data on American boys.
``What we‘re seeing is a symptom of a very serious public health problem,‘‘ said Herman-Giddens, noting that the long term physical and mental health impact of early puberty are not understood.
Being obese or overweight, which has been associated with premature puberty, may be one potential cause. Others include genetics, low birthweight, poor diet, lack of activity, and surprisingly, an absentee father or a non-relative male in the house have also been offered as explanations.
Scientists have also been exploring whether so-called ‘‘endocrine disrupters‘‘--a group of chemicals thought to interfere with hormonal function--might be spurring or delaying puberty, said Herman-Giddens.
John Peterson Myers, director of the W. Alton Jones Foundation and author of a book on chemical contamination and fetal development, said some of these chemicals have retarded sexual development in rat fetuses.
Among the most controversial of these chemicals are phthalate esters, which are found in toys, vinyl flooring, detergents, and cosmetics and lotions. The chemical and cosmetics industry says phthalates have been proven safe and that they have no role in causing early puberty.
``The science is not certain, but there is a plausible link,‘‘ contends Myers.Diana Zuckerman, executive director of the National Center for Policy Research for Women & Families, said she worries about the psychological impact of early puberty on young girls.
Previous studies have shown that girls who develop at a young age begin dating earlier, have sex sooner, are subject to more psychological stress, more behavioral problems, and were more likely to drink and smoke, said Zuckerman.
``No matter what they look like, they are still little girls,‘‘ she said. Zuckerman also added that early puberty places additional stress on parents who have to explain sexuality at a younger age.
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